High Action on CU24SE, Part 2

[Acnestes]

Hi All,
I'm re-posting this as a new thread as I'm afraid it might have gotten lost in the my aging original one.

I am still pondering the mystery of why the action on this guitar just won't go as low as I think it should. So, I have a couple or three questions for anyone with a 24SE of any variety, a few minutes and a good ruler:

1) At the very end of the fingerboard (the body end), on your guitar, what is the measurement between the top of the body and the top edge of the fingerboard? Mine measures 12/64" on both the treble and bass edges.

2) If I run a straightedge down the center of the fingerboard between the D and G strings and extend it till it touches the saddles, the measurement between the straightedge and the base plate of the vibrato is 11/64". What is it on your guitar?

2) Does it occur to you that, when viewed upside down, the marker on the 24th fret looks kind of like a penguin, and the one on the 21st kind of like a cat climbing or leaping upward? Or have I been staring at this for too long?

Thanks again!

 

[Mozzi]

Hi All,
I'm re-posting this as a new thread as I'm afraid it might have gotten lost in the my aging original one.

I am still pondering the mystery of why the action on this guitar just won't go as low as I think it should. So, I have a couple or three questions for anyone with a 24SE of any variety, a few minutes and a good ruler:

1) At the very end of the fingerboard (the body end), on your guitar, what is the measurement between the top of the body and the top edge of the fingerboard? Mine measures 12/64" on both the treble and bass edges.

2) If I run a straightedge down the center of the fingerboard between the D and G strings and extend it till it touches the saddles, the measurement between the straightedge and the base plate of the vibrato is 11/64". What is it on your guitar?

2) Does it occur to you that, when viewed upside down, the marker on the 24th fret looks kind of like a penguin, and the one on the 21st kind of like a cat climbing or leaping upward? Or have I been staring at this for too long?

Thanks again!

None of this has any impact on the 'action' of the guitar!!!

1- It could be 1cm, 1.5cm or just 0.5cm - it doesn't matter to the action at all. There are some guitars with a higher fingerboard on the body but can still have a low action.
2- Again, makes no difference at all to the action.
3- what difference does it make to the action? I have always just seen the Owl and the Hawk Landing

The only things that matter to the action is the nut slots, the neck relief and the saddle height. The distance between the nut and saddles (also known as scale length) can affect string bending ease, but the action is the height of the string above the fingerboard so the height of the body to the fingerboard or the gap between fingerboard and bridge plate have no impact on the action at all.

 

[Acnestes]

None of this has any impact on the 'action' of the guitar!!!

1- It could be 1cm, 1.5cm or just 0.5cm - it doesn't matter to the action at all. There are some guitars with a higher fingerboard on the body but can still have a low action.
2- Again, makes no difference at all to the action.
3- what difference does it make to the action? I have always just seen the Owl and the Hawk Landing

The only things that matter to the action is the nut slots, the neck relief and the saddle height. The distance between the nut and saddles (also known as scale length) can affect string bending ease, but the action is the height of the string above the fingerboard so the height of the body to the fingerboard or the gap between fingerboard and bridge plate have no impact on the action at all.

1&2) It has to do with the angle of the neck, which is set, relative to the bridge saddles and implies a limit beyond which they cannot be lowered. I am trying to establish whether the construction of my guitar is typical or not.

3) Well, you caught me on that one. It is not actually relevant to the action.

 

[Mozzi]

1&2) It has to do with the angle of the neck, which is set, relative to the bridge saddles and implies a limit beyond which they cannot be lowered. I am trying to establish whether the construction of my guitar is typical or not.

3) Well, you caught me on that one. It is not actually relevant to the action.

The Neck angle may well be important to a guitar but the IMPORTANT aspect is the saddle height, the nut slot depth and the relief of the neck. How high the neck is at the body has NO relevance at all and neither does the distance from the bridge either. If the Slots on the nut are not cut deep enough and bridge saddles are set too high, combined with a neck bow upwards, the action will be extremely high - regardless of the neck height. If the relief is set right, the nut slots cut deep enough and the saddles adjusted to be at the right height, the action will be low. You can have a neck set an inch above the body - as long as the neck relief, nut slots and bridge is set correctly. The distance of the bridge from the end of the neck is only important to the scale length - a 25.5" scale length will be half an inch further back from the neck than a 25" scale (with the same 24 fret neck) or closer if you have a 24.5" scale length.

If you can't get the action low enough, you need to check the relief of the neck (hence you have a truss rod), the depth of the nut slots and the bridge saddle heights - assuming the trem is set correctly and not lifted up from the string tension of course...

 

[Acnestes]

The Neck angle may well be important to a guitar but the IMPORTANT aspect is the saddle height, the nut slot depth and the relief of the neck. How high the neck is at the body has NO relevance at all and neither does the distance from the bridge either. If the Slots on the nut are not cut deep enough and bridge saddles are set too high, combined with a neck bow upwards, the action will be extremely high - regardless of the neck height. If the relief is set right, the nut slots cut deep enough and the saddles adjusted to be at the right height, the action will be low. You can have a neck set an inch above the body - as long as the neck relief, nut slots and bridge is set correctly. The distance of the bridge from the end of the neck is only important to the scale length - a 25.5" scale length will be half an inch further back from the neck than a 25" scale (with the same 24 fret neck) or closer if you have a 24.5" scale length.

If you can't get the action low enough, you need to check the relief of the neck (hence you have a truss rod), the depth of the nut slots and the bridge saddle heights - assuming the trem is set correctly and not lifted up from the string tension of course...

Thank you for all that. As it happens, though, I am not completely new to this, having been at it since I first agonized over my shiny new Epiphone Casino in 1967, so I do have a pretty fair grasp of the principles involved at this point.

The issue that I am dealing with is that with the vibrato set very low (using a 1.5mm Allen key as a shim, by the John Mann method) and parallel to the body and with the truss rod set so that the fingerboard is flat or with just a hair of relief, getting the action just barely to spec (which is pretty conservative) requires essentially bottoming out the saddles on both E strings, which matches neither the myriad photos I see, which show a good bit of clearance under the saddles, nor the descriptions of what I should be seeing.

What I kind of suspect is that either the neck socket is a bit too deep or that the neck itself at that point is a bit thin, either of which would produce less clearance between the top of the body and the top of the fingerboard (12/64" on mine, as I mentioned), and that means more distance between the fingerboard and the strings, in this case more than the saddle adjustment can deal with.

At this point I'm planing to file down the saddles a bit so I can have some room to adjust either way. Nevertheless, I'm curious to see how the measurements I mentioned compare to other guitars of the same model to see if mine is really atypical, as I suspect it might be. If all else fails, I'll bring a caliper to Guitar Center.

 

[Collywobbles]

Thank you for all that. As it happens, though, I am not completely new to this, having been at it since I first agonized over my shiny new Epiphone Casino in 1967, so I do have a pretty fair grasp of the principles involved at this point.

The issue that I am dealing with is that with the vibrato set very low (using a 1.5mm Allen key as a shim, by the John Mann method) and parallel to the body and with the truss rod set so that the fingerboard is flat or with just a hair of relief, getting the action just barely to spec (which is pretty conservative) requires essentially bottoming out the saddles on both E strings, which matches neither the myriad photos I see, which show a good bit of clearance under the saddles, nor the descriptions of what I should be seeing.

What I kind of suspect is that either the neck socket is a bit too deep or that the neck itself at that point is a bit thin, either of which would produce less clearance between the top of the body and the top of the fingerboard (12/64" on mine, as I mentioned), and that means more distance between the fingerboard and the strings, in this case more than the saddle adjustment can deal with.

At this point I'm planing to file down the saddles a bit so I can have some room to adjust either way. Nevertheless, I'm curious to see how the measurements I mentioned compare to other guitars of the same model to see if mine is really atypical, as I suspect it might be. If all else fails, I'll bring a caliper to Guitar Center.

The neck angle does matter as it effectively controls the height the bridge needs to be set at. If the neck angle is very shallow the the bridge need to be low, and vice versa. I have posted these pictures before in another related thread [https://forums.prsguitars.com/threads/trem-question.34749/page-2] but this is how low my own US-made Custom is set. As you can see it's much lower than notional factory spec. I'd just accept your guitar needs the bridge setting lower than spec and (assuming it's working OK and not catching on the guitar's body) forget about filing down the saddles. The trem in the pictures works fine, returns to pitch, and holds tune beautifully. I also suspect this is how it left the factory.

This thread [https://forums.prsguitars.com/threads/blocking-a-prs-tremolo-need-advice.34665/#post-433666] also has a couple of videos by John Ingram, who worked with Paul in the early days and set up most of the early guitars leaving the factory. The videos show how he sets up a PRS. There are lots of setup videos on YouTube - John Mann (already mentioned in this thread) and John Ingram are the two I'd trust. John Ingram covers setting the trem block and mentions the height it's set at depends on neck angle.

 

[Acnestes]

Thanks for the input. That's about where my bridge is. Actually John Mann himself originally put it in, using the 2.5 mm Allen Key he uses in the video, but I since reset it using a 1.5mm, which puts it just about where yours is. The neck angle relative to the body is zero, btw. But my saddles are not even that high.
I think that what I'm looking at is an Indonesian made guitar with less than perfect QC where the tolerances piled up (or not) in one direction rather than averaging out, the result being that the guitar was able to squeak through inspection with the adjustments really at the limit rather than comfortably in the middle of their range. Filing down the saddles a few 64ths is an easy enough fix and I have zero complaints about the guitar otherwise.
I had more or less convinced myself what the problem was but I was more than anything curious that no one else on the forum seems to have reported anything like it, though I did see some reference to high action in the product reviews for this particular model, which was billed as a limited edition from either Musicians Friend or Guitar Center.
Thanks again!

 

[Collywobbles]

Thanks for the input. That's about where my bridge is. Actually John Mann himself originally put it in, using the 2.5 mm Allen Key he uses in the video, but I since reset it using a 1.5mm, which puts it just about where yours is. The neck angle relative to the body is zero, btw. But my saddles are not even that high.
I think that what I'm looking at is an Indonesian made guitar with less than perfect QC where the tolerances piled up (or not) in one direction rather than averaging out, the result being that the guitar was able to squeak through inspection with the adjustments really at the limit rather than comfortably in the middle of their range. Filing down the saddles a few 64ths is an easy enough fix and I have zero complaints about the guitar otherwise.
I had more or less convinced myself what the problem was but I was more than anything curious that no one else on the forum seems to have reported anything like it, though I did see some reference to high action in the product reviews for this particular model, which was billed as a limited edition from either Musicians Friend or Guitar Center.
Thanks again!

John Mann has a machine shop so I'm sure he could mill them down if you wanted to go that route (probably better than filing them). He did some work on an old trem with seized grubscrew for me that I was very pleased with. Perhaps have a chat with him if he set your guitar up as he knows as much as anyone about these trems having designed/manufactured the original version. Good luck.

 

[Acnestes]

Job done! The tool of choice was Mitchell's Abrasive Cord. I took each of the saddles, clamped them in a padded vise at a comfortable angle, threaded the cord through the same path the string would take and flossed away until I removed about 2/32" from the string contact point, which only takes a few minutes. The abrasive cord (which comes in different diameters) does a perfect a job as you could want. Very controllable and leaves a polished, rounded surface just like you started with. I now have excellent action with all the saddles happily within their adjustment ranges with air underneath and matching the fingerboard radius.

Now I'm happy!

 

[Acnestes]

I finally got around to photos, so here's the result of my labors. I left some shots of the rest of the guitar in a thread called "My New Friend" on the Electric Instruments forum.